Garand
I've hunted my Garand a bit, and have the same experience.....in dim light, I cannot get a sight picture. I'd wager I lose 15-20 min or more of shooting light with a peep. So much so that I will not hunt a peep in the evenings. On rifle or bow.
From my experience bow hunting, and using a peep on the bowstring, with a trit pin or lit pin, you will see the trit dot, but finding the deer through the peep will still be difficult.
One thing I've considered for the Garand, is one of the scout scope mounts and a coarse reticuled low power IER scope. You could even put a red dot up there. Such an arrangement on my Savage Scout / bolt works OK.
Yeah, optic on a Garand, non traditional for sure, but it likely will help.